Table 6.
Temporal lag | Bootstrap ratio | Spatial extent | Talairach coordinates |
HEM | Gyral location | Brodmann area | Significant post hoc ANOVA results | ||
---|---|---|---|---|---|---|---|---|---|
x | y | z | |||||||
Easy > hard | |||||||||
Left hemisphere | |||||||||
3 | 5.42 | 197 | −35 | −26 | 59 | Left | Precentral gyrus | 4 | |
2, 4 | 5.19 | 81 | −46 | −29 | 58 | Left | Postcentral gyrus | 2 | |
3 | 4.02 | 10 | −9 | −21 | 45 | Left | Medial frontal gyrus | 6 | |
3 | 3.92 | 11 | −12 | 40 | 40 | Left | Superior frontal gyrus | 8 | |
Right hemisphere | |||||||||
2 | 4.13 | 71 | 43 | −32 | 42 | Right | Inferior parietal lobule | 40 | |
Hard > easy | |||||||||
Left hemisphere | |||||||||
4 | −5.41 | 112 | −39 | 2 | 43 | Left | Middle frontal gyrus | 6 | |
3 | −3.84 | 11 | −45 | −56 | −16 | Left | Fusiform gyrus | 37* | R: group × difficulty and group × task |
3 | −3.62 | 10 | −31 | 39 | 15 | Left | Middle frontal gyrus | 46* | R: difficulty |
Right hemisphere | |||||||||
2–4 | −9.97 | 758 | 13 | −92 | 3 | Right | Cuneus | 17* | R: task × difficulty |
Note: Temporal lag represents the time after event onset, when a cluster of voxels exhibited a contrast effect of interest. The bootstrap ratio threshold was set to ±>3.28, and identified dominant and stable activation clusters. The spatial extent refers to the total number of voxels included in the voxel cluster (threshold = 10).The stereotaxic coordinates are measured in millimeters, and gyral location and Brodmann areas (BAs) were determined by referring to Talairach and Tournoux (1988). The last column presents the highest order significant effect (P < 0.05) observed from the ROI-based post hoc group × task × difficulty repeated-measures ANOVAs. Regions marked with * were ROIs for which mean activity was extracted and plotted in a bar graph. R, significant effects for retrieval activity; HEM, cerebral hemisphere in which the activation occurred.